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>> The fun thing is, apparently SSD has
>>
>> 1. Reached price levels where Normal Humans can potentially afford them.
>>
>> 2. Reached capacities where you might actually buy this stuff.
>>
>> Interesting times ahead, eh?
>
> Indeed, I've a friend in Scotland who has a Thinkpad with an SSD in it
> and the performance is good, but the battery life is also quite good (I
> think he said he gets 10 hours out of a single battery).
Lots of laptops have offered an SSD option for a while now. The problem
has always been that the price is a bit insane. Looks like prices are
starting to become reasonable now - although I see 100x differences in
the reported I/O performance being quoted for different models. (!!)
Also, I'm quite impressed with my own laptop. Usually laptops /claim/ to
run for 8 hours or something, but /actually/ run for about 20 minutes.
The 8 hours figure applies only if you leave the laptop turned on but
not *doing* anything. :-P But my current laptop /really does/ run for
several hours without needing recharging. It's pretty neat...
(My laptop also has /actual 3D performance/ too. I had no idea laptops
could do that now!)
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On 23/01/2012 3:43 PM, Invisible wrote:
> Unexpected, but true...
<boggle>
--
Regards
Stephen
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On Mon, 23 Jan 2012 15:50:19 +0000, Invisible wrote:
>>> The fun thing is, apparently SSD has
>>>
>>> 1. Reached price levels where Normal Humans can potentially afford
>>> them.
>>>
>>> 2. Reached capacities where you might actually buy this stuff.
>>>
>>> Interesting times ahead, eh?
>>
>> Indeed, I've a friend in Scotland who has a Thinkpad with an SSD in it
>> and the performance is good, but the battery life is also quite good (I
>> think he said he gets 10 hours out of a single battery).
>
> Lots of laptops have offered an SSD option for a while now. The problem
> has always been that the price is a bit insane. Looks like prices are
> starting to become reasonable now - although I see 100x differences in
> the reported I/O performance being quoted for different models. (!!)
>
> Also, I'm quite impressed with my own laptop. Usually laptops /claim/ to
> run for 8 hours or something, but /actually/ run for about 20 minutes.
> The 8 hours figure applies only if you leave the laptop turned on but
> not *doing* anything. :-P But my current laptop /really does/ run for
> several hours without needing recharging. It's pretty neat...
>
> (My laptop also has /actual 3D performance/ too. I had no idea laptops
> could do that now!)
My new laptop has 3D performance as well - it's a "desktop replacement".
But I typically get about 2-3 hours off the battery in powersave mode.
Most laptops that I've used for a bit, the battery typically is good for
about an hour to an hour and a half. But a new battery generally will do
well.
Jim
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On Mon, 23 Jan 2012 15:43:34 +0000, Invisible wrote:
>>>> So how much power do you think it takes to run 50,000 computers, plus
>>>> air conditioning for them, if each has (say) 150W power supply?
>>>
>>> As I say, the point is that most people will never see 50,000
>>> computers in one place all at once.
>>
>> That isn't really necessary to be able to do the math....
>
> Sure, that's the great thing about math; it always works right, unlike
> intuition. ;-)
>
> But it's not a calculation most people would bother to make, because the
> power consumption of a PC is "negligible".
Actually not so much. A 450 W power supply draws a reasonably
significant amount of power.
> In a similar vein, the heat output of a normal human in a large empty
> room is also negligible. But weirdly, if you put /a lot/ of humans in a
> room, no matter how big that room is, they manage to raise the
> temperature of the whole room. Unexpected, but true...
Not unexpected at all - completely rational and in line with the laws of
thermodynamics.
Jim
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>> But it's not a calculation most people would bother to make, because the
>> power consumption of a PC is "negligible".
>
> Actually not so much. A 450 W power supply draws a reasonably
> significant amount of power.
Yeah, generally you only find power supplies that meaty on high-end
"leet gamer" PCs. I'm guessing Google doesn't use those.
Even 450W is peanuts compared to what my kettle uses. (3.6 kW)
>> In a similar vein, the heat output of a normal human in a large empty
>> room is also negligible. But weirdly, if you put /a lot/ of humans in a
>> room, no matter how big that room is, they manage to raise the
>> temperature of the whole room. Unexpected, but true...
>
> Not unexpected at all - completely rational and in line with the laws of
> thermodynamics.
Sure. But humans don't think in terms of thermodynamics, they think in
terms of common everyday experience.
Random fact: If you're dangling from a wire above a pit of molten lava,
YOU DIE. In particular, you do /not/ have to actually *touch* the lava
for it to kill you. An entire lake radiates easily enough heat to cook a
small elephant, never mind your skinny arse. And that's without even
taking into account convection and all the toxic gasses.
Really, that scene from Indiana Jones and the Temple of Doom is
laughably implausible... But most people actually have no clue exactly
how hot lava really is. It's not in their everyday experience.
Actually, going back to my previous point: The amount of /moisture/
emitted by a normal human is absurdly small. And yet, put enough of them
in a room, and it can get astonishingly moist in there! o_O
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Invisible <voi### [at] dev null> wrote:
> >> Heh, I still remember looking at one of the stacks, and seeing that it
> >> had *seven* 4.2 GB drives in it. (Remember, in 1997, those suckers where
> >> EXPENSIVE.) I remember feeling slightly giddy trying to compute how much
> >> total storage space such a monster RAID setup... Ah, the memories.
> >
> > Indeed, I still recall that the Fortune 50 company I worked for a decade
> > ago had an EMC storage array with 750 GB of storage in it....
> >
> > My new *laptop* has a drive that big in it. I've got about 4 TB of
> > storage here at home now.
>
> The fun thing is, apparently SSD has
>
> 1. Reached price levels where Normal Humans can potentially afford them.
Yep, I own two of them. A 60GB as a system drive for my desktop and a 120GB for
my laptop.
The performance improvement really is remarkable. And its not the burst speed
that is interesting but the random access transfer rates.
> 2. Reached capacities where you might actually buy this stuff.
>
> Interesting times ahead, eh?
>
> (Personally, I still can't figure out why SSD isn't several /million/
> times faster than a mechanical spinning disk, but hey...)
The read performance is actually mostly limited by the host interface (SATA3 is
up to 600MB/s nowadays) and the memory management of the SSD, write perfomance
largely depends on how fast the flash cells can be programmed.
Regards
Aydan
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Invisible <voi### [at] devnull> wrote:
> Actually, going back to my previous point: The amount of /moisture/
> emitted by a normal human is absurdly small. And yet, put enough of them
> in a room, and it can get astonishingly moist in there! o_O
I just had a look in Wikipedia:
1 human sweats about 400ml to 1l per day.
Now you just need the number of people and the size of the room to know how fast
it saturates.
Regards
Aydan
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On 23-1-2012 11:38, John VanSickle wrote:
> On 1/15/2012 6:05 AM, Orchid XP v8 wrote:
>>>> And also I'm assuming this is not cheap, so management do not want.
>>>
>>> Making something truly zero down-time is exceedingly expensive.
>>
>> Yeah, reducing down-time isn't usually too bad, but /zero/ down-time
>> requires going to absurd lengths.
>
> When I was stationed at Onizuka AFB, California (the Blue Cube, for
> those who live or work near the south end of the San Francisco Bay), we
> had two large SATCOM dishes, called Sun East and Sun West.
>
> One chronic problem was that getting downtime for preventive maintenance
> was as difficult as pulling gold teeth from a chicken. The user
> community (who was and always will be better connected than the
> maintenance community) were as stubborn as mules about allowing any
> downtime for any reason.
>
> "Hey, what if we took each dish down, once every six months, and do all
> of the preventive maintenance specified in the technical orders?"
>
> "No, no, we need those dishes up 24/7. Denied."
>
> You'll never guess what the result was.
Difficult.
my first guess would be that after 9-12 months the system failed for
more than twice the time of the provocative maintenance.
but...
you said I couldn't guess. so that is not what happened.
ergo, the system was reliably working for 10 years until it was replaced
by a better system with a small overlap in time.
...
No that can not be right, because if that was the case I guessed it, and
I couldn't.
...
but, but, that would be true of every other guess...
...
...
Ah, I got it, I can not *guess* it, therefore I must *know* the answer:
After 9-12 months the system failed for more than twice the time of the
provocative maintenance.
--
tip: do not run in an unknown place when it is too dark to see the
floor, unless you prefer to not use uppercase.
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On 23-1-2012 16:43, Invisible wrote:
>>>> So how much power do you think it takes to run 50,000 computers, plus
>>>> air conditioning for them, if each has (say) 150W power supply?
>>>
>>> As I say, the point is that most people will never see 50,000 computers
>>> in one place all at once.
>>
>> That isn't really necessary to be able to do the math....
>
> Sure, that's the great thing about math; it always works right, unlike
> intuition. ;-)
>
> But it's not a calculation most people would bother to make, because the
> power consumption of a PC is "negligible".
>
> In a similar vein, the heat output of a normal human in a large empty
> room is also negligible. But weirdly, if you put /a lot/ of humans in a
> room, no matter how big that room is, they manage to raise the
> temperature of the whole room. Unexpected, but true...
<boggle indeed>
I think the rule of thumb is that a person is about 100W. but any amount
of power will heat any room even if only slighly unless:
a) the room is infinite in size
b) the room was warmer than a person to begin with (i.e. warmer than a
person that is not cooled by outside temperatures)
--
tip: do not run in an unknown place when it is too dark to see the
floor, unless you prefer to not use uppercase.
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On Mon, 23 Jan 2012 12:22:44 -0500, Aydan wrote:
> Invisible <voi### [at] devnull> wrote:
>> Actually, going back to my previous point: The amount of /moisture/
>> emitted by a normal human is absurdly small. And yet, put enough of
>> them in a room, and it can get astonishingly moist in there! o_O
>
> I just had a look in Wikipedia:
> 1m³ of air at 20 can carry roughly 30ml of water (as vapour).
> 1 human sweats about 400ml to 1l per day.
> Since "normal" room air usualy has about 50% humidity that leaves about
> 15ml/m² for the sweat. That would mean 1 human can saturate 1 - 2.5 m³
> of air per hour.
> Now you just need the number of people and the size of the room to know
> how fast it saturates.
You'd also need to know the current relative humidity to know how
saturated it is before you start adding people to the room.
0% humidity is quite rare - in fact, I don't know that it's possible on
Earth other than in an artificial environment. I live in a desert
climate (though not in the desert), and while we do easily hit below 20%
relative humidity, we don't hit 0. (In fact, it's snowing right now)
Jim
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